scholarly journals Reaction of active nitrogen with oxygen

1967 ◽  
Vol 45 (22) ◽  
pp. 2837-2840 ◽  
Author(s):  
A. S. Vlastaras ◽  
C. A. Winkler
Keyword(s):  
Reaction Time ◽  
Oxygen Atom ◽  
Gas Phase ◽  
Rate Constant ◽  
Analytical Method ◽  
Order Rate Constant ◽  
Maximum Amount ◽  
Active Nitrogen ◽  
Tube Reactor ◽  
Different Levels

The maximum yields of oxygen atoms, estimated at different levels in a long-tube reactor by gas-phase "titration" with NO2, were equal for the reactions of active nitrogen with NO and O2. In this reactor, the maximum oxygen-atom production from the oxygen reaction, determined by the amount of N2O3 produced with excess NO2, was found to correspond to the NO "titration" value for the active nitrogen and not to the maximum amount of HCN produced in the active nitrogen – ethylene reaction. A second-order rate constant, [Formula: see text] [Formula: see text]was obtained for the active nitrogen – oxygen reaction.Experiments in a short reactor showed that the validity of the analytical method based on the trapping of N2O3 depended upon adequate reaction time for the NO + NO2 reaction to occur.

Low Temperature CVD of TiN from Ti(NR2)4 and NH3: FTIR Studies of the Gas-Phase Chemical Reactions

1993 ◽  
Vol 335 ◽  
Author(s):  
Bruce H. Weiller
Keyword(s):  
Reaction Time ◽  
Gas Phase ◽  
Rate Constant ◽  
Chemical Vapor ◽  
Rate Limiting Step ◽  
Tube Reactor ◽  
Ftir Spectrometer ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Phase Chemical

AbstractThe gas-phase chemical reaction between Ti(NMe2)4 and NH3 is a critical step in the Metallorganic Chemical Vapor Deposition (MOCVD) of TiN at low temperatures. We have examined this reaction using a flow-tube reactor coupled to an FTIR spectrometer. A sliding injector provides control over the reaction time and the kinetics of reactive species can be measured as a function of the partial pressure of an added reagent. The disappearance of Ti(NMe2)4 was measured as a function of reaction time and NH3 pressure at 26°C. The resulting bimolecular rate constant is (1.1±0. 1) x 10-16 cm3molecules−1s−1 Dimethylamine is observed as a direct product from this reaction consistent with other studies. We have also measured the rate constant using ND3 and find a substantial isotope effect, kh/kd ≈2.4± 0.4. This indicates that H-atom transfer is involved in the rate limiting step. We show that these results can be explained by a mechanism comprised of transamination reactions with NH3.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

IR Diagnostics of MOCVD Reaction Chemistry

1992 ◽  
Vol 282 ◽  
Author(s):  
Bruce H. Weiller
Keyword(s):  
Reaction Time ◽  
Gas Phase ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Flow Tube ◽  
Tube Reactor ◽  
Ftir Spectrometer ◽  
Ir Diagnostics ◽  
Trimethyl Aluminum ◽  
Phase Chemical

ABSTRACTThe gas-phase chemical reactions in the Metallorganic Chemical Vapor Deposition (MOCVD) of A1N and TiN have been studied using IR spectroscopy. The products formed from the reaction of trimethyl aluminum (TMA) and NH3 were compared to those from the reaction of TMAwith NF3 using a static gas-phase IR cell. Reaction with NH3 is rapid at 25 °C, and the IR spectrum of the product is consistent with the acid-base adduct (CH3)3Al-NH3. At 25 °C, no reaction between TMA and NF3 was observed. However, at 58 °C a slow reaction occurredto give (CH3)2AlF. The reaction of Ti(N(CH3)2)4 with NH3 was also studied using a flow-tube reactor with a sliding injector port that provides control over the reaction time between two reactive flows. By monitoring the disappearance of Ti(N(CH3)2)4 as a function of NH3 partial pressure and reaction time, we have obtained a preliminary estimate of the rate constant as ∼ 10−16 cm3 molecule−1 s−1 at 25 °C. This result confirms that the reaction is rapid even at room temperature and demonstrates the utility of the flow-tube reactor and FTIR spectrometer for studies of MOCVD chemistry.

THE RATE OF REACTION OF ACTIVE NITROGEN WITH AMMONIA AND ETHYLENE

1962 ◽  
Vol 40 (1) ◽  
pp. 5-14 ◽  
Author(s):  
A. N. Wright ◽  
C. A. Winkler
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Reaction Times ◽  
Active Nitrogen ◽  
Atom Concentration ◽  
Initial Flow ◽  
Flow Rates ◽  
Average Value ◽  
Rate Of Reaction ◽  
Excited Nitrogen

The rate constants for the reactions of C2H4 and NH3 are determined by termination of the reactions in the gas phase after different times of reaction. The average value for the rate constant of the N atom–C2H4 reaction at 150 °C is 1.8 × 1010 cc mole−1 sec−1, when the initial N-atom concentration is determined from the maximum production of HCN. The average value for the rate constant for the over-all reaction of NH3 with excited nitrogen molecules, at 104 °C in the "poisoned" system, and 83 °C in the "unpoisoned" system, for low initial flow rates of NH3, or short reaction time, is 2.2 × 1010 cc mole−1 sec−1. The decrease in value of this rate constant at higher initial flow rates of NH3 and longer reaction times in the "poisoned" system indicates that the species responsible for NH3 decomposition is generated during the decay of N atoms in the presence of NH3. The value for the NH3 reaction is discussed in terms of energy transfer.

THE REACTIONS OF ACTIVE NITROGEN WITH ETHYLENE AND DEUTERATED ETHYLENES

1966 ◽  
Vol 44 (22) ◽  
pp. 2691-2701 ◽  
Author(s):  
Kenneth D. Foster ◽  
P. Kebarle ◽  
H. B. Dunford
Keyword(s):  
Hydrogen Atom ◽  
Mass Spectrometer ◽  
Rate Constant ◽  
Reaction Times ◽  
Order Rate Constant ◽  
Second Order ◽  
Atomic Nitrogen ◽  
Large Excess ◽  
Active Nitrogen ◽  
Initial Concentration

The reaction of active nitrogen with ethylene and deuterated ethylenes has been investigated by use of a mass spectrometer. The rate of disappearance of atomic nitrogen in the presence of ethylene appears to obey the equation[Formula: see text]where kapp is an apparent second order rate constant and [ethylene]0 is the initial concentration of added ethylene. However, exceptions to this equation are found at 0.6 Torr either for short reaction times or for small concentrations of added ethylene, and apparently for short reaction times at 2.6 Torr when a large excess of ethylene is added. Where the above equation is obeyed, kapp = (3 ± 1) × 10−13 cc molecule−1 s−1. The formation of C2D4 in the reaction of active nitrogen with C2D3H is interpreted as further evidence for the importance of hydrogen atom reactions in intermediate steps of the reaction of active nitrogen with ethylene.

Investigation of the Reaction of Naphthalene with 0(3P) in the Gas Phase

1989 ◽  
Vol 44 (11) ◽  
pp. 1119-1121 ◽  
Author(s):  
H. Frerichs ◽  
R. Koch ◽  
M. Tappe ◽  
H. Gg. Wagner
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Ground State ◽  
Kinetic Data ◽  
Atomic Oxygen ◽  
Flow System ◽  
Order Rate Constant ◽  
Mass Spectrometric ◽  
Reaction Channels ◽  
Electronic Ground

The rate of the reaction between naphthalene and atomic oxygen in the electronic ground state was determined in a discharge flow system with mass spectrometric detection for temperatures between 362 and 773 K. All measurements were performed in an excess of O atoms over hydrocarbon. The second order rate constant was determined to be Kinetic data are compared with data about the reactions of other aromatic substances and atomic oxygen in the ground state. Some possible reaction channels are discussed

CATALYZED RECOMBINATION OF NITROGEN ATOMS, AND THE POSSIBLE PRESENCE OF A SECOND ACTIVE SPECIESIN ACTIVE NITROGEN

1960 ◽  
Vol 38 (12) ◽  
pp. 2514-2522 ◽  
Author(s):  
Roger Kelly ◽  
C. A. Winkler
Keyword(s):  
Rate Constant ◽  
Pressure Range ◽  
Order Rate Constant ◽  
Active Species ◽  
Third Order ◽  
Active Nitrogen ◽  
Atom Concentration ◽  
Order Rate ◽  
Excited Molecules ◽  
Atom Decay

The reactions of ethylene, ethane, and ammonia with active nitrogen have been studied over the pressure range 0.3 to 4 mm usinganunheatedreaction vessel. The object was to determine why each reactant shows, as is well-known, a smaller extent of reaction at lower temperatures than would be predicted from the atom concentration. It was concluded that ethylene probably brought about homogeneouscatalyzedrecombination, i.e. the process [Formula: see text] followed by N + N•C2H4 → N2 + C2H4. The over-all third-order rate constant appeared to be very large, about 1.8 × 10−28 cc2 molecule−2 sec−1. The behavior of ammonia was quite different from that of ethylene and it was, in fact, possible to show that the extent of reaction was not governed by the instantaneous atom concentration at all. The results can be explained qualitatively, however, if it is assumed that excited molecules formed in the course of homogeneous atom decay constitute a second active species in active nitrogen. This view serves also to explain the failure in such work as that of Kistiakowsky etal. to observe ammonia destruction or excited molecules when especially low atom concentrations are used. The few experiments involving ethane were sufficient to show that the reactivity was low for a different reason than with ethylene.

THE LIFETIME OF THE STATE OF N2

1965 ◽  
Vol 43 (2) ◽  
pp. 369-374 ◽  
Author(s):  
L. F. Phillips
Keyword(s):  
Decay Rate ◽  
Rate Constant ◽  
Rate Constants ◽  
Blue Emission ◽  
Order Rate Constant ◽  
The State ◽  
Active Nitrogen ◽  
First Order ◽  
A Value ◽  
Mean Lifetime

The decay of the blue emission from the active nitrogen – iodine flame has been measured at iodine pressures down to 1.4 × 10−4 torr. Extrapolation of the decay rate to zero iodine pressure yields a value of 0.89 ± 0.41 s−1 for the first-order rate constant in absence of iodine, corresponding to a mean lifetime of 1.1 s for the [Formula: see text] state of N2. The rate constants for the reactions[Formula: see text]and[Formula: see text]are (2.6 ± 0.3) × 10−11 exp (−68 ± 34/RT) and (8.3 ± 1.2) × 10−14 cm3 molecule−1 s−1 respectively.

Flow Tube Kinetics of Gas-Phase Cvd Reactions

1993 ◽  
Vol 334 ◽  
Author(s):  
Bruce H. Weiller
Keyword(s):  
Ir Spectra ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Rate Constant ◽  
Room Temperature ◽  
Flow Tube ◽  
Tube Reactor ◽  
Ftir Spectrometer ◽  
Kinetics Of ◽  
Phase Chemical

AbstractThis paper explores the use of a flow-tube reactor coupled to an FTIR spectrometer to study gas-phase chemical reactions in CVD systems. We show that our apparatus can generate reliable kinetics data by reproducing the literature rate constant for the reaction between O3 and isobutene. We present data from this apparatus on two technologically important systems: TiN from Ti(NMe2)4 (TDMAT) and NH3 and SiO2 from tetraethoxysilane (TEOS) and O3. The results presented include kinetics data for the reaction of Ti(NMe2)4 with NH3 and ND3 at room temperature and the IR spectra of the products from the reaction of TEOS with O3 at 175°C.

A PULSED ION SOURCE FOR THE STUDY OF UNIMOLECULAR AND BIMOLECULAR REACTIONS OF GAS-PHASE IONS

1965 ◽  
Vol 43 (1) ◽  
pp. 159-174 ◽  
Author(s):  
T. W. Shannon ◽  
F. Meyer ◽  
A. G. Harrison
Keyword(s):  
Reaction Time ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Rate Constant ◽  
Thermal Energy ◽  
Ion Source ◽  
Operating Characteristics ◽  
Bimolecular Reactions ◽  
Molecule Reaction ◽  
Gas Phase Ions

A pulsed ion source has been constructed for use with a magnetic-deflection mass spectrometer. With this source the time between ion formation and withdrawal for analysis can be controlled and varied in a known manner. The design and operating characteristics of the source are discussed and a technique is described for the measurement of ion withdrawal times using the pulsing technique. The rate constant for the ion molecule reaction[Formula: see text]has been determined for the reaction of thermal energy ions using reaction time as the experimental variable. The equivalent reactions in the deuteriomethanes have also been studied. Preliminary results obtained in the study of the unimolecular fragmentation of the cyclohexadiene, toluene, and spiroheptadiene parent ions are presented.

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